Mark Walsh is set to partner Yanworth in the Stan James Champion Hurdle at the Cheltenham Festival on Tuesday week.
Barry Geraghty has ridden the seven-year-old on each of his eight starts over hurdles to date, but misses the Festival through injury.
And after discussions with owner JP McManus over the weekend, trainer Alan King confirmed Walsh will be his replacement.
"Mark Walsh is going to come over and have a sit on Yanworth and Uxizandre, probably on Thursday, and the plan is that he'll ride both horses at Cheltenham," the Barbury Castle handler told Press Association Sport.
"I don't know him at all, but he's a very good rider.
"I've been very happy with both horses since their last runs.
"Everything has gone well."
Yanworth is unbeaten in three starts this season, winning the Coral Hurdle at Ascot, the Christmas Hurdle at Kempton and the Kingwell Hurdle at Wincanton.
He is the general 7-2 favourite for the Champion Hurdle, with Uxizandre 6-1 to claim another victory in the Ryanair Chase.